[5] During the Mexican–American War, he was attached to the paddle-frigate USS Mississippi and participated in the capture of all but one of the towns on the Mexican coast taken by the Navy.

[6] "Subsequently he was the superintendent of the construction of all the armour-clads built west of the Alleghenies, involving an expenditure in the aggregate of seven millions of dollars".

[7][8] During the mid-1870s, King—as chief engineer of the Navy—made many visits, official and private, to Europe, to collect information relating to shipbuilding, machinery, and other aspects of naval warfare.

[3] In 1877, he produced a report to Congress entitled, European Ships of War and Their Armament, Naval Administration and Economy, Marine Constructions and Appliances, Dockyards, etc., etc.

[2] King's critical evaluations of naval architecture assumed that Congress might soon fund new designs for a re-equipped American Navy.